Genetically modified green algae could produce stored energy in the form of hydrogen gas, Australian scientists from the University of Queensland have said in a new study published in the current issue of the Plant Biotechnology Journal.
According to Associate Professor Ben Hankamer, if successfully scaled up, this process could complement or be an alternative to the present carbon based economy.
'We urgently need to develop and install new CO2-free energy production systems. Our systems offer one solution for this,' said Prof. Hankamer.
He said, during experiments, the team successfully increased the sunlight-capturing efficiency of the single-celled photosynthetic algae (Chlamydomonas reinhardtii), by silencing some of the genes responsible for producing light-harvesting proteins.
Algae have evolved two kinds of photosynthesis, one of which produces hydrogen gas under low-sulphur conditions.
Prof. Hankamer said, in order to harvest hydrogen gas from a bioreactor, a concentrated mass of algae in sealed vats could be stored that would pump out hydrogen each time the Sun is shining.
He said, as the algae were inefficient at capturing sunlight, with 90 percent of the light falling on them given off as heat or fluorescence, the team used RNA interference (RNAi) to engineer a strain of algae to make the process more efficient.
The result - the team engineered a strain of algae that only used the light it needed, rather than wasting it as fluorescence and heat.
Prof. Hankamer said, in a bioreactor this would mean that the light the strain would not need would pass through to other light-harvesting algae deep inside the mass.
'Since the new strain has fewer light-harvesting proteins, it is a lighter green than the natural one, which also helps light to penetrate deeper into the bioreactor. The engineered algae are more resistant to light damage than natural strains,' ABC online quoted Prof. Hankamer, as saying.
He said, the findings were significant, as it meant that given the same amount of light, the algae would survive longer and reproduce more, thus possibly generating more hydrogen gas.
As of now, Prof. Hankamer and his colleagues have already patented a strain of the algae that is more efficient at converting captured sunlight into hydrogen gas.
The next step, he said, would be to improve the light-capturing efficiency of this strain.
'We have to improve the efficiency of the process in order to make it economically viable,' said Prof. Hankamer.